Railway dry-dock.



J. L. CRANDALL.

RAILWAY DRY DOCK. APPLICATION FILED APR. 11. 1918.

Patented Feb. 4, 1919.

2 SHEET$-SHEET l- I 1 for,

J. L. CRANDALL. RAILWAY DRY DOCK.

APPLICATION FILED APR-17.1918.

Patented Feb. 4., 1919.

2 SHEETS-SHEET 2.

UNITED STATES PATENT OFFICE.

JAMES L. CRANDALL, OF MALDEN, MASSACHUSETTS, ASSIGNOR TO THE CRANDALL ENGINEERING COMPANY, OF BOSTON, MASSACHUSETTS, A CORPORATION OF MAINE.

RAILWAY DRY-DOCK.

Specification of Letters Patent.

Patented Feb. 4, 1919.

To all whom it may concern:

Be it known that I, JAMES L. CRANDALL, a citizen of the United States, and a resident of Malden, county of Middlesex, and State of Massachusetts, have invented an Improvement in Railway Dr -Docks, of which the following is a speci cation.

My invention relates to railway dry docks or marine railways movably arranged on ways, and has more particular reference to the means connected between the dock and the power actuated means employed to move the dock along its way.

It is common practice in railway dry docks to employ a power driven shaft located at one extremity of travel of the dry dock, and to connect said shaft throu h a plurality of draw chains with the dry ock. The chains are commonly arranged to pass over sprockets on the power driven shaft, and are connected to the dock through equalizing means which may be arranged in a drawhead connected to the dock or incorporated into its structure. The rotation of-the driven shaft serves to wind the draw chains over sprockets fixed to the shaft and to thereby move the dock along the ways. There is designed to be no relative motion between chains, but because of unavoidable slight inequalities in the length of the links composing the chains, a smallamount of relative motion of the chains does take place, and the equalizing device associated with the dry dock serves to distribute the load equally between all of the chains connected with the dock and with the power driven shaft.

The chains connected between the driven shaft and the dry dock are commonly arranged in loops; that is, a chain passes over a sprocket on the driven shaft and around a pulley associated with the equalizing means arranged in the draw head of the dock and over another sprocket on the driven shaft, thus forming a single loop between the driven' shaft and the draw head. A sufiicient number of such loops are arranged between the driven shaft and the draw head and between which, due to th equalizing device, the load is equally distributed.

It sometimes happens, from various causes, that a chain forming a side of one of the loops breaks; in which event, the load formerly taken by the loop must now be taken by the other loops connected between the driven shaft and the dock.

' The breakage of a chain forming one side of a loop throws that portion of the load which had been taken by both sides of the loop on to the remaining loops; which loops will, in such case, be unduly loaded. The breaking of the chain forming oneside of a loop serves to entirely destroy the loop, so far as its taking any stress 1s concerned, even though the other side of the loop remains sound and unbroken; and the effect is thereby the same as though both sides of the loop had broken.

The object of my invention is in the provision of means whereby, upon the breakage of a chain comprising one side of a loop,

the other side of the loop may continue to be operatively connected between the power driven shaft and the dry dock and continue to take a share of the load, and the load may be so distributed through the equalizing means that all the chains connected between the power driven shaft and the dock, including the chain forming a portion of the broken loop, have equal stresses therein. With this arrangement, but one half the stress taken by theloop when entire, must be. distributed to the remaining loops, instead of all the stress, as has heretofore been the case. In such case, with a plurality of loops, the small added stress that each chain receives is usually insufiicient to dangerously overload it.

The means I employ to accomplish the object of my invention is in the provision of stops attached to each side of the loop of chains and arranged on the chains but a small distance above the draw head. In the event of a chain breaking between the power driven shaft and a stop, the slack chain between the stop and a solid portion. of the draw head will be taken up or dis tributed through the equalizing means to all the other chains connected between the power driven shaft and the draw head, and the chain comprising the other side of the loop will pull against the stop, and the stress taken by the broken loop will be distributed equally through the remaining other side of the loop and the remaining loop. The effect of, the sto is as though the broken end of the chain is solidly connected, through the equalizer, with the draw head.

Figure 1 is a partial view of a railway dry dock and hauling mechanism, embodying my invention.

Fig. 2 is a partial side elevation of the railway dry dock and hauling mechanism,

embodying my invention.

Fig. 3 is a plan view of a chain stop.

Fig. 4: is an elevation of a chain stop.

Fig. 5 "is a 'front elevation of a haw'se pipe.

Fig.6 is a sectional view of thehawse "pipe on the line 66 of Fig. 5.

Fig. 7 is a diagrammatic representation of the chains and draw head, witha chain broken.

Fig.8 is a detail of a. modified arrangement of hauling mechanism.

As here-shown, an end of the railway dry dock, represented by 10, is provided with a draw head 11, which is connected thereto by the pins 12 and links13, althoughthe draw .25 head maybe otherwise connected to the dry dock. The draw head 11 rests upon a cradle 14, which is movably arranged on theways 15, upon which the dock rests.

The draw head includes, at its portion thereof connected with the dock, two beams or girders16, spaced apartto form a substantially box structure, and -maintained in said relationbythe pivot blocks 16 to which said girders are secured and through which the drawingstresses are transmitted to the pins 12 and links 13. A number of pulleys 17 are arranged in the space between the girders 16, being preferably equally spaced from one another, and arerotatably mount- 7 40 ed on pins 17"fiXedin the draw head 11.

A second box girder, formed of the girders 18, comprisesthe foremost part of the draw head,"and is connected with. the rear girders 16 by'means-of the short struts or columns 19, which serve to maintain said girders 16 and 18 in spaced relation-andalso serve to take the stress that-is arranged: to fall upon the girders 1=8when a chain' is broken, and-a stop, to be hereinafter more fully described, is moved into engagement with :said girders 18 i to transmit the load fIOm'R'lDFOkGDlOOptO the remaining loops of'chains of the hauling mechanism. The meanswhereby thedry dock may be moved 7 65 along the ways 15 includes the shaft 20, disposed at the upper end of travel of the dock and which maybe rotated by any suitable n1eans,:not necessarily shown. A number of sprockets 21' arefixedon said shaftiir suitable spaced relation, and a number of chains, each arranged to form a loop comprising the sides 23,-.and are passed around said sprockets-and'extend to the draw head. The chains-forming loops 28 arepassed through openingsBB in .hawse pipes 24 secured-bethereof secured to and between the girders 16 adjacent the ends thereof, and is looped alternately around the pulleys 27- secured-to the links 26 and the fixed pulleys 17, pivotally mounted-between the girder 16 in the 7 rear part of the draw head structure.

Said chain 28 comprises what is termed a bridle upon which the pull of the draw chains is taken. By arranging the chain 28 alternately between the pulleys 25, connected through the links 26 and pulleys 27 tothe loops of the draw chain, and pulleys l7 pivoted between the girders 16, the stresses of theidraw chains comprising'the separate loopsmay be equalized; for if one loop has a tendency to shorten fasterthan other loops, due to inequalities in thelengths ofthelinks forming the chains, then said loop will tend to pull up on that portion'of the bridle chain wound overits pulley 25, which'pull will be resisted equally by'all of theother loops ofthe draw chains; and consequently eachloop, or the chain included in the-sides 23' and 23 thereof, may be stressed equally at all times. i

The stop incorporating my invention and as shown in detail in'Figs. 3 and-4, may com.- prise two bars 31and=32, having grooves-33 therein arranged to receive a link 34e-of-the chain'28 which isadaptedto be clamped between said bars 31 and'32by-bolts'35. The bars 31 and 32 are ofsuch a width thatthey are prevented" from entering the opening '36 infthe hawsepipe 24; and, therefore, upon the breaking ofachain between a sto an'd theipower driven shaft, that: portion of the chain between astop and the pulley27 will be drawn into the draw head until thestop comes intoengagement with'the outer face ofthe hawse pipe21 and further movement of-the chain is thereby prevented. i

The stop maybe of any other: special or desired shape, as its function is to prevent the chain,when it becomes broken, from being drawn through the opening in the hawse pipe and from 'arounditslpulley 27, and to operably secure the broken end to the draw head. i I

The positiono'f the clamp'31 upon the draw chainsmay be varied within comparatively widelimits; but it isadvi sable to position the clamps'as close to thedraw'head as. possible," 1 leaving only sufficient space thercbetween' to provide for relative movement of the two-portions of: a' loop,due-. to theinequalities inlength of the links comprising the chains, such that in the normal operation ofthe .chainsjn moving the dock along the wayspthe stops will not-.comeinto contact with the cross head. Upon the breakage of the chain, however, between the stop and the power driven shaft, the stop should be sufficiently close to the draw head that there is but small rearward movement of the link 26, upon which are pivoted the pulleys 25 and 27; so that the loop in the bridle chain 28 around the pulley 17 is not entirely straightened.

Upon the breakage of a chain composing a side of a loop, the strain is consequently relieved from one of the loops of the bridle chain 28, and consequently the dock begins to sli back and the chains continue to wind up until all of the slack has been taken by the remaining loops in the draw chains. The stop on that portion of the chain which is broken comes in contact with the hawse pipe secured in the front end of the draw bar, or to the front girders 18 of the draw head, and further movement of the chain is thereby prevented. This condition is diagrammatically illustrated in Fig. 7. The total load of the dock is now taken up by all of the remaining loops of chains, and by the remaining unbroken side of the ruptured loo Iii the illustration shown in Fig. 1, if one of the ten reaches of chain, forming the five loops extending between the driven shaft 20 and the draw head breaks, there remain nine reaches of chain between which the load is equally distributed. The effect of the stop on the broken end of one of the chains is as though the end of the chain were secured directly to the draw head. The load of the dry dock is now equally divided between the remaining reaches of chain, as all of the load is transmitted to the dock structure throiwh the bridle chain 28, as before, and the brea ing of the chain comprising a side of a loop results in the loss of but one side of a loop instead of the entire loop, as heretofore.

Although I have described and shown the reaches of chain as being connected in loops and passed over pulleys yet the reaches of chain may be otherwise arranged to serve the same purpose.

The pulleys may be considered, in effect, continuous levers, and where the relative motion between the two reaches of chains comprising a loopis but slight, then the pulleys may be replaced by actual levers.

Such an arrangement is shown in Fig. 8, in which the pulleys 25 and 27 connected by the link 26 are replaced by the whifile trees and 61, with the reaches 6262 of chain wound over the driving shaft connected to the ends of the whifile tree 60, and the whifile tree 61 connected through chains 6363 to the ends of separate whiffle trees 64 pivoted at their central points to the frame of the draw head.

The whiflie trees 61 and 64, connected through the chains 63 are in effect the equivalent of the bridle chain 28 passed over the pulleys 17 pivoted to the draw head or dock structure.

As before, stops may be arranged on the reaches of chain to opera'bly connect the unbroken reach of chain, though a whiille tree 60, with the draw head, upon the breaking of the other reach of chain completing the loop; or stops or abutments 65 may be secured to a member 66 of the draw head or dock structure adjacent the ends of the whiflie trees 60 which, upon the breaking of a reach of chain, serve to connect the other reach of chain, through the whiiile tree with the draw head or dock structure, these, in effect, acting in all respects, similar to the stops arranged upon the reaches of chain.

I claim 1. In combination with a railway dry dock movably arranged on ways, and a hauling device to move said dock along the ways, of a plurality of draw chains extended in loops between said device and the dock, an equalizing device associated with the deck, the chains comprising the sides of a loop being connected through the loop to the equalizing device, and means to transfer the load of a chain comprising a side of a loop to the other side of the loop and to the other loops of chains upon the breaking of said chain.

2. In combination with a railway dry dock movably arranged on ways, and a hauling device to move said dock along the ways, of a plurality of draw chains extended in loops between the device and the dock, an equalizing device associated with the dock, said loops of chains being connected through the loops with the equalizing device to thereby equalize the load on the chains, and a chain stop associated with the chains adjacent the dock and operable to connect one side of a loop through the equalizing de vice to the dock upon the breaking of the chain comprising the other side of the loop to thereby distribute the load taken by the broken chain to the other side of the loop and the other loops.

3. In combination with a railway dry dock movably arranged on ways, and a hauling device to move said dock along the ways, of a. plurality of draw chains extended in loops between the hauling device and the dock, an equalizing device associated with the loops of chains and the dock, the chains comprising a loop being connected through the loop and the equalizing device with the dock and adapted for relative movement, and a chain stop on the chains adjacent the dock and operable upon the breaking of a chain comprising one side of a loop to connect the other side of the loop to the dock and distribute the load taken by the broken chain to the other side of the loop and the other loops.

In combination with a railway dry said device and through equalizing'means with the draw head, and chain stops secured to said chains adjacent the draw head movable into engagement with the draw head, upon the breaking of the side of a loop 10 to distribute the pull of that side of the loop between the other side of the loop and the other loops.

In testimony whereof, I have signed my name to this specification, in the presence of two subscribing Witnesses.

JAMES L. CRANDALL.

Witnesses T. T. GREENWOOD, H. B. DAVIS.

Comes of'this patent ma be obtained for five cents each, by addressing the Commissioner of Eatentfl,

Waahlngten, I). G. 

